The present invention relates to an improved airbag system which will, based on a predetermined input, adjust the deployment potential of the airbag appropriate for the occasion. In general, the system, by adjusting the flow path from the inflator to a non-airbag inflating escape path, will allow for a more aggressive deployment based on input such as recognition of a larger or unbelted occupant and will allow for a less aggressive deployment based on input such as recognition of a smaller or belted occupant. Because the system automatically adjusts the flow paths of a fully powered inflator rather than requiring a uniquely designed inflator per application, much more standardized inflators can be used for a wide variety of vehicles to achieve a greater economy of scale. In order to adapt the improved airbag system to a different vehicle, rather than any mechanical or geometrical differences, the algorithms of the controlling electronics would merely be modified to incorporate new variables such as vehicle structure stiffness, length of crumple zone, airbag volume, airbag vehicle location, airbag to occupant distance, etc. Further, should for any reason, such as the gathering and processing of more crash statistics, the deployment rate potential needs to be changed retroactively, the change would merely require modifying the controlling electronics deployment parameters such as by a software upgrade.
In a preferred embodiment of the present invention, the adaptive airbag system comprises an airbag module having an airbag inflator, an airbag inflator encasing reaction canister, and an airbag. The reaction canister incorporates an overload valve comprising a spring and two end caps that are coupled to a spring compressor. The overload valve is ported such that inflation fluid that passes through the overload valve, is allowed to pass harmlessly through the vehicle firewall and to the atmosphere outside of the vehicle cockpit, or into some other harmless location. The compressive load on the spring and valve, much as an automatically focusing Further, once designed and installed in a vehicle, should one desire to change the inflator deployment rate, the existing inflator would have to be physically replaced with another inflator of the desired deployment rate. Additionally, because of the increased number of activating components relied upon, it is believed that the reliability and repeatability of inflators of the above described type is inherently reduced. Thus although these types of inflators are an improvement over that which has heretofore been available, they add considerable cost to the airbag system, they require a uniquely designed inflator for each significantly different vehicle in which they would be installed, and they are limited in their amount of adjustability.
Other methods used to adaptively adjust an airbag are found in U.S. Pat. Nos. 5,707,078 and 6,068,288. U.S. Pat. Nos. 5,707,078, and 6,068,288 are expressly incorporated herein by reference. camera lens that adjusts to changing fields of view, continuously adjusts as required to incoming signals. In response to a requirement for a less aggressive deployment, the compressor adjusts so as to apply a lesser compressive load to the spring and consequently to the valve such that a lower reaction canister air pressure will cause the valve to open. In response to a requirement for a more aggressive deployment, the compressor adjusts so as to apply a greater compressive load to the spring and consequently to the valve such that a higher reaction canister air pressure is required to cause the valve to open. In this fashion, the adaptive airbag system is adjustable from the entire gas flow being directed to the airbag, to the entire gas flow being diverted from the airbag in the case where the an airbag breakout force is less than the force required to open the overload valve. This embodiment has the advantage of compensating for a higher than intended/desired inflation pressure/force by reactively allowing the overload valve to open a greater amount. Further this embodiment has the advantage of compensating for an inflation pressure/force that drops off too rapidly by closing completely or partially during inflation gas deployment. Such advantage can provide for a better deployment pressure curve over the entire duration of inflation gas deployment. In order to avoid compressor fluttering, the compressor constantly adjusting to the most minute sensed change in deployment requirement, and to increase the life of the compressor and valve, the controlling electronics provide dead zones in the ranges of inputs that cause valve adjustment. For example, the compressor could adjust the valve so as to reduce the potential gas flow to the airbag upon the sensing of a weight on the vehicle seat of less than 100 pounds, and yet the compressor would not increase the potential gas flow to the airbag until the sensing of a weight on the vehicle seat of more than 105 pounds. Thus once adjusted to a load of 100 pounds, the compressor would not respond to minor fluctuations in seat loading over 100 pounds but less than 105 pounds until after experiencing a load of 105 pounds or greater or less than 100 pounds.
Thus it is an object of this invention to provide an adaptive airbag system that automatically adjusts to a required degree of deployment.
It is a further object of this invention to provide an adaptive airbag system that compensates for performance variability in an inflation device.
It is a further object of this invention to provide an adaptive airbag system that provides the situation appropriate amount of inflation fluid to the airbag and allows the remainder to the inflation fluid to escape outside of a vehicle cockpit, thus avoiding any unnecessary inflation fluid inhalation by a vehicle occupant.
It is a further object of this invention to provide an adaptive airbag system having deployment parameters that are retroactively redefineable by modifying the electronic algorithms that control airbag deployment.